Mitigating biofouling of polyamide thin-film composite RO membrane modified with AgNPs and pSBMA: an evaluation close to the actual SWRO desalination application scenario

ABSTRACT The long-term sustainability of beneficial effects resulting from the modification of polyamide thin-film composite (PATFC) membranes with zwitterionic poly(sulfobetaine methacrylate) (pSBMA) and silver nanoparticles (AgNPs) in real-world application scenarios remains uncertain. This study used response surface methodology and innovative anti-biofouling evaluation method to optimize the conditions for AgNP- and pSBMA-co-modified PATFC membranes, with reverse osmosis seawater desalination as the test application scenario. A 180-day continuous seawater treatment test was conducted to evaluate the long-term sustainability of anti-biofouling resistance. Results indicated that loading AgNPs before grafting pSBMA enhanced their stability during use and cleaning. Co-modification under optimal conditions led to a 6.3% improvement in membrane flux reduction over long-term operation. The effect of AgNPs was significant for 30 days, while pSBMA remained effective until the end of the test. Water contact angle measurements, confocal laser scanning microscopy, and quorum sensing signal molecule analysis revealed anti-bioflouling improvements due to the hydration layer and electrostatic barrier from pSBMA, as well as quorum sensing inhibition and disinfection from AgNPs. These findings confirm the discount effectiveness and feasibility of the pSBMA and AgNPs co-modification technique during long working time, offering valuable insights into modification operations and anti-biofouling mechanisms.